I believe the gesture you are referring to is one hand is to represent the state of Michigan and the other hand is pointing to where Michigan is on that “map”. Sorry about the pun, can’t help myself sometimes.

In response to mooshu who said:
Why do Michiganders, but especially Detroit folks, do that… lame hand gesture?

correct. every year i head up to the tip of the ring finger for a family vacation. yes, it is a weird hand gesture… but no more weird than the “state bird of NJ” (no, not the goldfinch).

In response to plywood who said:
I believe the gesture you are referring to is one hand is to represent the state of Michigan and the other hand is pointing to where Michigan is on that “map”. Sorry about the pun, can’t help myself sometimes.